Marked by an admirable, but certainly not spectacular performance by Michelle Williams — in a role she’s arguably not very suited for — some wonderful costuming, set design and locations, and a stand-out supporting turn by Judi Dench, there aren’t many other favorable things to say about “My Week With Marilyn,” a slight drama with a reputable cast that still feels through and through like a superficial, made-for-TV Lifetime movie.

We’re highly aware it’s often incredibly reductive and unfair when TV-like criticisms — small in scope, episodic in nature, unsubstantial — are lobbied at small screen directors making their feature-film debut like this one, Simon Curtis (a BBC director known for “Cranford,” “Five Days” and “David Copperfield“), but this shoe unfortunately fits very squarely. A large part of the problem is the screenplay and source material. Based on the books, “The Prince, The Showgirl and Me” and the memoir “My Week with Marilyn,” by Colin Clark — a third assistant director on the British set of 1956’s Laurence Olivier-directed “The Prince and the Showgirl, which starred Olivier and Marilyn Monroe — the source material not only seems remarkably dubious, but thin. This fleeting and airy fairy tale doesn’t seem like a story substantial enough to merit a feature film (though maybe a movie on TV would suffice) and the screenplay by Adrian Hodges does little to help to give the story much import. Also, featuring a delusional lead (Clark), it’s a hard one to root for.

Opening with some arduous and on-the-nose voice-over, we’re introduced to a young Colin Clark (played by Eddie Redmayne), an idealistic 23-year-old and aspiring filmmaker who defies his cultured and affluent parents’ art-school wishes, traveling to London and attempting to get a job at Lawrence Olivier’s film production house (his well-to-do family are friendly with Vivien Leigh, played by Julia Ormond, the wife of Mr. Olivier). Eager and determined, Clark eventually lands a gig as not only Olivier’s personal assistant, but also as third-AD on the romantic comedy that the renowned actor is about to start – “The Prince and the Showgirl.”

The film’s lead, one Marilyn Monroe (Michelle Williams), sets foot on British soil for the first time not only to star in the picture, but to vacation on her honeymoon with new husband, celebrated playwright Arthur Miller (Dougray Scott). With Monroe making her maiden voyage to England, the press is typically frenzied and the public nearly insatiable. The predictable chaos of flashbulb-shot footage ensues.

Even before a difficult film shoot commences, Olivier and Monroe are at odds, in part due to the presence of Paula Strasberg (Zoë Wanamaker), Monroe’s method-acting coach who’s approach is diametrically opposed to Olivier’s. Making matters worse is Monroe’s diva-like behavior — arriving everywhere hours behind schedule, making cast and crew wait until she is ready and has “found” her character (her teacher of course enabling every “I’m still undeveloped” notion). But these issues are just the tip of the iceberg, and deeper still are her fragile psyche and fear of being unlovable, amplified by a dangerous combination of deep insecurities and lots of pills and booze.

And while the film within the film and Monroe are struggling to find their footing, Clark begins to enter the starlet’s inner circle, which includes her distrustful and enabling press agent Milton Greene (Dominic Cooper). Mostly, it’s by chance; as Olivier’s frustration and impatience with Monroe builds, Clark is often sent to fetch Monroe in her make-shift trailer to see if she’s ready, and a friendly bond begins to grow. Securing that connection is circumstance; Arthur Miller, at his wits’ end with his new bride, travels back to New York, and Monroe becomes even more vulnerable and needy, with Clark inadvertently starting to fill the role of warm and friendly man in her life. And during those sometimes brief moments together, innocent mistakes – Clark accidentally bumps into the star stark naked when looking for a script in her room – begin to take on “isn’t he cute?” friendly tones that build to camaraderie, affection, companionship and, eventually, a skewed kind of illusive love.

Thus becomes the push and pull of the picture. Clark finding himself the object of Monroe’s whims and attentions as a sort of band-aid for her moodswings – much to the chagrin of her inner circle and the film crew. But “My Week With Marilyn” is so airy, romantic and illusory, it’s easy to believe that Clark’s original memoir might have been nothing more than a huge delusion (a criticism that’s already been pitched at the book). While just a kid – one that is warned several times that these romantic excursions won’t last – his fantasies about their relationship border on hallucinations, and it’s hard to want to take his side. His artificial, foolishly cheerful demeanor is one that the picture also unfortunately shares.

For Williams, the challenges are immeasurable. Her interpretation of Monroe is flighty and soft, a romantic dreamer with deep-seated issues behind the glamorous veneer, but the script doesn’t allow her character to go very deep. That screenplay also offers next to no insight into the personality of Monroe that you haven’t read a thousand times – the toll of stardom was too much, she was needy, she had emotional issues, she was a pill addict, etc. Wiliams does a commendable job at impersonating the icon without veering into grotesque pantomime, but it’s not the kind of stunning performance we’ve witnessed from her of late, and certainly not her best in recent years. While the Weinstein Company will likely throw all their muscle behind the actress for a Best Actress Oscar nom, based on quality alone, she’s far from a lock (though it’s so pleasingly middle of the road, like “The King’s Speech,” the picture and her performance could therefore end up being a strong contender).

While Branagh and the rest of the cast (which includes Emma Watson and Toby Jones) do adequate work within the confines of subpar material, it’s only Judi Dench as the empathetic and encouraging Dame Sybil Thorndike who registers as something special in the picture (and her role is so small, it doesn’t count for much).

Musically, ‘Marilyn’ is problematic as well to the point of distraction. While Alexandre Desplat does provide the lovely theme, Conrad Pope — mainly an orchestrator who has worked several times with John Williams (“Minority Report,” “A.I.,” “The Adventures of Tintin“) — takes the composing center stage, mostly filling the drama with “isn’t this all so delightful?” musical cues. Of course there’s also, “isn’t this sad?” and “isn’t this a dreadfully serious pickle we’ve gotten ourselves into?” but none of these motifs do the film any favors.

Completely free of subtext (it’s as if it doesn’t exist), the film is marred by egregious exposition at every single turn, whether in painfully written voice-over or contrived dialogue. The screenplay even offers title cards for background context and then dares to give near-embarrassing “this is who I am and how I was feeling at the time” voice-over to set the stage. The first 10 minutes of the picture could almost be seen as a parody of what you might see in the made-for-TV movies on Ovation, or the Oxygen channel, but sadly, the film doesn’t possess an ironic bone in its body. The script also pointlessly follows a brief romance between Clark and a wardrobe girl played by Emma Watson, but it’s a huge dangling chad and why the film doesn’t bother to simply excise these immaterial scenes is a mystery.

“My Week With Marilyn,” is not terrible, it’s got a terrific cast who do their best with average material, and its engaging enough, and tolerable enough, that in some circles it will be seen as a big crowdpleaser, but there’s very little meat on the bone. It’s charitably capable and its decent performances make it relatively absorbing at times, but ultimately “My Week With Marilyn” is fluff of the superficial type, a valiant misstep for Williams, and a minor and inconsequential work regardless of its place among the Oscar hopefuls vying for position this fall. [C]